For everyone who doubts that a team up could ever happen between Fox and Marvel, straight from the big heads mouths:

"In October 2012, Lauren Shuler Donner, the producer of 20th Century Fox's X-Men film series, expressed interest in having the X-Men characters appear in the Marvel Cinematic Universe. Shuler Donner said, "I would love it. I personally have close ties to Marvel because of Kevin Feige, because Kevin worked for me. But to take our characters and mingle them in the way that they were written, yeah, absolutely."[97]Mark Millar, who was hired in September 2012 to consult on all of Fox's future Marvel films, expressed similar sentiments in an interview, saying "Fox have said that they want to build a cohesive universe and I’d personally like this to work in complement to the Marvel one. It would be cool if these universes didn’t contradict each other so if you went to see Spidey, The Avengers, the X-Men, etc, as a viewer you would have no idea that all three are coming from different studios. I’d love to make it look like they’re all just happening in one place."

I never said it would happen now but in the future there's a chance once Fox establishes there universe